To enable an eNodeB to dynamically allocate an appropriate resource to a terminal, the terminal needs to report power headroom information of the terminal to the eNodeB. The eNodeB adjusts a current transmit power of a terminal device according to a power headroom report (Power headroom report, PHR for short). If a power headroom report sent by a terminal to a base station is inaccurate, a scheduling resource allocated by the base station to the terminal is inappropriate, further causing problems such as increased interference between terminals, inadequate resource scheduling and a reduced uplink throughput.
To resolve the foregoing problems, in the prior art, a terminal calculates a power headroom (Power headroom, PH for short), a transmit power on an uplink shared channel, and a transmit power on a physical uplink control channel (Physical Uplink Control Channel, PUCCH for short) based on a downlink path loss of a cell-specific reference signal (Cell Reference Signal, CRS for short) of a serving cell and other related parameters, and reports a power headroom report to a base station.
However, as mobile broadband develops rapidly and smartphones become popular, global mobile data traffic reaches a compound annual growth rate up to 67%. Moreover, distribution of network traffic is extremely uneven, and capacity requirements in hot spot areas grow explosively. Network coverage, spectrum utilization, and the like that can be implemented by an existing low-band network can no longer meet user requirements. Therefore, future 5G networks will be established at a high band up to 100G. However, when the prior art (in a current LTE system, cell coverage is omnidirectional antenna coverage) is used to perform high-band networking, a series of problems occur, such as small network coverage, high power consumption, a high path loss, low spectrum efficiency, and a low system capacity. Consequently, at the high-frequency networking stage, it is excessively difficult to implement a method in which a terminal calculates a power headroom, a transmit power on an uplink shared channel, a transmit power on a physical uplink control channel, and the like according to a downlink path loss of a CRS of a serving cell and other related parameters. Therefore, at the high-frequency networking stage, a problem that urgently needs to be resolved is to find a method for calculating a power headroom, a transmit power on an uplink shared channel, and a transmit power on a physical uplink control channel, and for sending a power headroom report to a base station, so that the base station adjusts a transmit power on a terminal device side according to the power headroom report.